all you do is replace the reciever drier with a new one ( as it stores oil and will be full of the stuff; there is a compatibilaty issue with the 134a). Then you get new ports. The whole kit to do the comversion start to finish costs about 40 dollars +labor and reciever drier. You then need to get someone to pull a vacuum on the system. I like to pull 25-30" of vacuum for at least 30 minutes when converting a/c systems. Then you just put in the PAG oil and 134a refrigerant and your set to go.